Today, I played the first puzzle after getting a 30 second ad. After finishing, the calendar showed it was saved & I exited the game & reopened it. Now the calendar said I had no games completed today.
I then completed the same game after receiving a 30 second ad, but this time there was a Skip AD button which I clicked after 5 seconds. I completed the game, exited & reopened the game. The calendar now shows the game is completed successfully.
The people who say this is related to 30 second advertisements seem to be correct.